1. Field of the Invention
The invention relates to integrated circuit nonvolatile memory. In particular, the invention relates to programmable resistive nonvolatile memory, such as phase change memory.
2. Description of Related Art
Nonvolatile memory stores data without requiring a continuous supply of power. Thus, nonvolatile memory is useful in not only integrated circuits with nonvolatile storage as a primary purpose, but also integrated circuits with mission mode circuitry besides just data storage.
However, multi-function circuitry that combines multiple functions in this manner is associated with more complex fabrication. If the multi-function integrated circuit was originally designed only with functions other than storage as its primary functions, the fabrication process must be modified to fabricate the nonvolatile storage. It would be desirable if such modifications could be made while minimizing the changes to the fabrication process of the integrated circuit.
Even with multi-function integrated circuits that are designed from the ground up with the nonvolatile memory in mind, processing compatibility issues are presented by the differing fabrication requirements of the nonvolatile memory and the remaining circuitry. It would be desirable if multi-function integrated circuits with nonvolatile memory were designed to minimize compatibility issues during processing.